Opposition parties say New Zealand will have little credibility at international climate change talks given the Government has chosen not to sign up to the next stage of the Kyoto Protocol.
The annual United Nations climate change conference begins on Monday in Doha, Qatar, where negotiators from nearly 200 countries will continue to try to strike a global deal to reduce greenhouse gas emissions.
The talks are aimed at securing a new treaty by 2015 that would cap emissions from all countries including developing nations and come into force by 2020.
Climate Change Issues Minister Tim Groser says it makes more sense to work towards a binding global agreement than to sign up in the interim to the second phase of Kyoto, which covers countries making up only some 15% of emissions.
Labour and the Greens say the decision not to stick with Kyoto and the weakening of the Emissions Trading Scheme will affect New Zealand's ability to be taken seriously in the international negotiations.
Former New Zealand climate change ambassador Adrian Macey told Morning Report that developing countries may question New Zealand on its decision not to sign up for the second phase and ask it to spell out exactly what it is doing.
Mr Macey says it would be possible to sign up to a commitment with nations outside the Kyoto Protocol that would closely resemble what it would be under the pact.